#include <bits/stdc++.h>
using namespace std;

int main() {
    int n, m;
    cin >> n >> m;
    
    vector<string> s(n);
    for(int i = 0; i < n; ++i){
        cin >> s[i];
    }

    for(int ignore = 0; ignore < n; ++ignore){
        vector<int> light(m, 0);
        for(int i = 0; i < n; ++i){
            if(i == ignore) continue;
            for(int j = 0; j < m; ++j){
                if(s[i][j] == '1'){
                    light[j] = 1;
                }
            }
        }
        auto isYes = [&]() -> bool {
            for(int i = 0; i < m; ++i){
                if(light[i] == 0){
                    return false;
                }
            }
            return true;
        };
        if(isYes()){
            cout << "YES" << endl;
            return 0;
        }
    }
    cout << "NO" << endl;
}   